1. Filed of the Invention
The present invention relates to a stationary induction apparatus, and particularly, to a stationary induction apparatus in which a structure for reduction of noise due to core excitation-vibration is improved.
2. Description of the Related Art
A traditional stationary induction apparatus, such as a transformer, a reactor, etc., is broadly made up of a core including plural core-legs formed by lamination of electromagnetic steel sheets, each thereof being composed of a magnetic material such as steel, etc., and a core-yoke, a core-tightening clasp for tightening a joint between the core-yoke and the core-leg in the direction of the lamination of the electromagnetic steel sheets, through the intermediary of an insulating material, and a tank in which not less than one winding, insulation-cylinder, and linear-spacer, respectively, are disposed around the core-leg, with an insulation-distance provided therebetween, thereby accommodating the core, the winding, the insulation-cylinder, and the linear-spacer, inside the tank filled up with a cooling insulating-medium.
With the core-yoke described as above, in order to ensure insulation thereof, an insulating sheet made of an insulating material is disposed along a lamination plane of the core-yoke to be tightened up by the core-tightening clasp through the intermediary of the insulating sheet. For the insulating sheet, use is made of a pressboard, etc., made up of a fiber, such as kraft pulp, etc., composed of cellulose as a main component, used as a raw material thereof, the fiber being subjected to processes of paper-making, lamination, and compression to be turned in a sheet-like shape. Further, for the core-tightening clasp, use is made of a clasp made of steel, or a stainless steel.
For example, with a stationary induction apparatus described in Patent Document 1, it is disclosed that a vibration insulator, such as a rubber sheet, and so forth, is disposed between an insulating sheet in contact with a core and a core-tightening clasp.